There has been proposed a laser light generation device which has a non-linear optical element in the resonator to effectively conduct wavelength conversion by the non-linear optical element, using high power density inside the resonator.
In the resonator utilized in such a laser light generation device, the non-linear optical element is provided between at least one pair of opposing mirrors that make up the resonator, and a fundamental-wave laser light enters into the resonator and passes through the non-linear element, for example. At this time, the distance between the mirrors (i.e., the light path length in the resonator) is controlled so as to coincide with an integer multiple of the incoming laser light, so that the laser light resonates in the resonator to generate laser oscillation.
For example, Patent Literature 1 discloses one example of the laser light generation device utilizing the resonator as described above. The laser light generation device according to Patent Literature 1 is configured to move the position of the mirror that makes up the resonator in the optical axis direction, and servocontrols the position of the mirror on the basis of the difference signal which is in proportion to the difference of the resonator length in relation to the incoming laser light of the resonator. By configuring like this, in the laser light generation device according to Patent Literature 1, the light path length of the resonator is automatically controlled so as to meet the condition under which the incoming laser light resonates in the resonator, and the resonance behavior of the incoming laser light of the resonator is stabilized.